OK, I foundthe problem with the equation:

The equation should be

Stress= PI * Pressure/2(OD/ID -1)

Thisquarters the stresses calculated in both barrels. So the stress of the 25-06 is33314 PSI, the stress in the .50 cal ML is 40,872.

Now all of a sudden there are many alloys capable of handling the .50 cal load at 25,000 psi. Alloys included, now are 1020 Mild steel with yield strength of50,800 psi.

Not much safety factor there, though.

4140 is a "smokeless" steel.If the 25-06is made ofoil quenched 4140 its design safety factorwould be6 to 1. Anyone know what alloy their ML is made of?

Happy Hunting, Phil